<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			var a=["aaa","bbb","cat"];
			var n=prompt("请输入一个字符串:","aaa");
			a.unshift(n);
			alert(a);
		</script>
	</head>
	<body>
	</body>
</html>